<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>task18</title>
    <script type="text/javascript" src="script/task18.js"></script>
</head>

<body>
    <div class="btnContainer">
        <input type="text" id="numInput">
        <button id="leftIn">左侧入</button>
        <button id="rightIn">右侧入</button>
        <button id="leftOut">左侧出</button>
        <button id="rightOut">右侧出</button>
    </div>
    <div id="numContainer"></div>
</body>

</html>
